How to Fix Rotted Drywall Around a Bathtub

by Fred Howe

There is only one reason that drywall around a tub begins to rot; the wrong type of drywall was installed during the bathroom’s construction. Water has managed to infiltrate the drywall and damage it. Often mold and mildew are present in the damaged areas as well. To properly repair the walls around the tub remove and replace all of the drywall on the affected walls. Replace the damaged drywall with mildew-resistant drywall. This type of drywall does not have a paper facing, rather it has a fiberglass facing, which is highly water, mold, and mildew resistant.

Prepare the Wall for New Drywall

1

Remove all of the plumbing fittings from the wall when you are replacing the drywall on the plumbing wall.

2

Make a hole in any affected drywall using the hatchet portion of a drywall hammer, or any other tool that produces a small hole in the drywall. Make the hole large enough so you can grasp the drywall with your gloved hand.

3

Cut the affected drywall down the vertical corners with a razor knife, and cut along the horizontal corners of the affected walls. Cut through the corner tape to facilitate the removal of the damaged drywall, while limiting the damage to adjacent unaffected walls or ceiling.

4

Remove sections of the damaged drywall by grasping it with your gloved hands, and pulling it away from the framing of the wall.

5

Remove all of the old fasteners, which remain in the wood framing after you remove the old drywall, use a screw gun when the fasteners are screws or a nail puller when the fasteners are nails.

6

Inspect the framing and insulation in the wall after you remove the old drywall. You must replace any water-damaged material before you install the new drywall.

Replace the Drywall

1

Measure from one vertical corner to the adjacent vertical corner, and transfer this measurement to a new drywall sheet.

2

Mark the drywall sheet, and cut it with a razor knife, along a 4-foot T-square. Always begin on the front side, or the finish side of the drywall sheet. Fold the drywall back on itself, and it will break along the cut you made on the front side of the sheet. Cut the backing material on the backside of the sheet along the “V” created by the folded drywall. Set aside the section of the drywall sheet you are removing for possible use later.

3

Position the cut drywall sheet on the wall. Make sure the bottom side edge of the drywall sheet extends down over the thin lip of the tub’s mounting flange. Leave a 1/8-inch gap between the bottom edge of the drywall sheet and the surface of the top of the tub. Caulking will be applied to this area after the drywall installation is completed.

4

Fasten the drywall sheet to the wall studs with nylon coated drywall screws, do not use drywall nails. Do not try to drive fasteners through the tub’s flange, always insert fasteners just above the flange, about 2 inches from the bottom edge of the drywall sheet. Install fasteners at 6-inch intervals along the perimeter and at 9-inch intervals in the field of the drywall sheet.

5

Measure and cut the upper drywall sheet for this wall. The length measurement should be very close to the measurement of the first drywall sheet you installed. The width measurement will be less than 4 feet. Measure the height of the opening from the top side edge of the installed drywall sheet up to the ceiling, and transfer this measurement to the drywall sheet you will be cutting. Cut the drywall sheet according to your measurements.

6

Install the upper drywall sheet so that its bottom edge is the factory edge, and its upper edge is against the ceiling. Fasten the drywall sheet in the same manner as the lower sheet.

7

Tape and finish the drywall in the same way you would regular drywall, except do not use paper tape. Use fiberglass mesh tape, which is water resistant.

Things You Will Need

Drywall hammer

Razor Knife

Work gloves

Face mask

Safety glasses

Drywall screw gun

Nail puller

Tape measure

4-foot drywall T-square

Drywall circle cutter

Nylon-coated drywall screws

Tip

If you need to make circular holes in the drywall to accommodate any plumbing fittings, always use a drywall circle cutter. Measure vertically and horizontally to the center of the plumbing fitting, and measure the diameter of the needed opening. Transfer these measurements to the drywall sheet prior to installation and cut the openings with the circle cutter.

Protect the tub’s finish by taping a drop cloth on the tub’s surface before you begin.

Warning

Always wear a mask if you see any sign of mold or mildew in the rotted drywall. Certain mold spores can be very dangerous if inhaled. If there is a lot of mold present, you should consult a certified mold abatement contractor before you proceed.

About the Author

Fred Howe, a writer since 2009, holds a B.S. in sociology from George Fox University. A retired correctional officer from Pelican Bay State Prison in California, Howe has also worked as a sous chef and catering manager.

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